Micro-pulse Lidar Network

Time period

December 2001 to Present

Project description

The Micro-pulse Lidar Network (MPLNET) is a network of lidar instruments run by a research team at the NASA Goddard Space Flight Center. These instruments comprise a high repetition, 2500Hz, diode pumped laser emitting at 523nm wavelength. The outgoing laser light is expanded through the 7-inch (17.8-centimeter) diameter receiver telescope to make the system eye-safe. The return lidar signal from the atmosphere is collected by the 7-inch diameter receiver, collimated, filtered with a narrow bandwidth filter, and sensed by a fiber-coupled single photon counting detector.

We convinced the MPLNET team to redesign the aft-optics of these instruments. These are the properties of the new design:

• more stable as all mounts are lockable without requiring epoxying
• improved thermal management
• less expensive to manufacture
• easier to adjust and align than previous versions, which reduces labor costs

We achieved backwards compatibility with almost all of the currently deployed MPLNET instruments. For example, a bolt-on change allows the laser, detector, and receiver telescope to be reused with the new aft-optics without modifying any existing components.

To date, two prototypes have been built: one is currently in testing; the other has completed testing and has been deployed. Some items have been modified and improved from these prototypes.

Currently, Welch Mechanical Designs can sell an improved revision A-model of the aft-optics structure. Optics and custom electrical cabling can also be supplied upon request.

Challenges and lessons learned

There were two main challenges to redesigning the MPLNET instruments: providing backwards compatibility and fulfilling packaging constraints. We overcame both challenges. First, all major components from existing instruments can be reused with the new aft-optics design. This was a signifiant requirement because there is such a large installed base of these instruments. Second, all the mechanical components had to fit within the small space dictated by the optics package while maintaining space for all desired adjustments.

Future

We are interested in supplying custom hardware for all needs of MPLNET. To achieve this goal, we are independently researching systems to improve the MPLNET instruments, as well as working to improve our existing designs. New systems soon to be available to MPLNET include a ruggedized, athermal 8-inch (20.3-centimeter) diameter, diffraction-limited telescope, and environmental enclosures that would allow an MPLNET to be stationed anywhere in the world.